Display devices containing fluids which can be switched between different fluid configurations to provide different optical characteristics are known. Several measures have been proposed to control the motion of the fluids within a picture element of the display device.
International patent application WO 2003/071346 describes such a display device. A movement of the fluids during switching is controlled by using an insulating layer on the first support plate having a particular shape to modify an electric field applied to the fluids. A special electrode structure or an inhomogeneous oil fluid layer may be used alternatively to control the fluid motion.
International patent application WO 2006/021912 describes a device having picture elements which have a shape that determines, upon switching, a preferred direction of movement of fluids within the picture elements.
International patent application WO 2004/104671 describes an optical switch containing fluids in which the shape of an electrode used to apply the voltage determines a preferred direction of movement of the fluids upon switching.
International application WO 2007/141218 describes a display device having a protruding hydrophilic part on an otherwise flat first support plate. The hydrophilic part operates as oil movement initiator. A disadvantage of this known display is that the arrangement of the protruding part requires an additional process step during the manufacture of the display.
It is an object of the present invention to provide a display device in which the control of the fluid motion can be made in a simpler manner.